ppapi/shared_impl/ppb_audio_shared.cc

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ppapi/shared_impl/ppb_audio_shared.h"

#include "base/logging.h"
#include "ppapi/shared_impl/ppapi_globals.h"
#include "ppapi/shared_impl/ppb_audio_config_shared.h"
#include "ppapi/shared_impl/proxy_lock.h"

namespace ppapi {

#if defined(OS_NACL)
namespace {
// Because this is static, the function pointers will be NULL initially.
PP_ThreadFunctions thread_functions;
}
#endif  // defined(OS_NACL)

AudioCallbackCombined::AudioCallbackCombined() : callback_1_0_(NULL),
                                                 callback_(NULL) {
}

AudioCallbackCombined::AudioCallbackCombined(
    PPB_Audio_Callback_1_0 callback_1_0)
    : callback_1_0_(callback_1_0),
      callback_(NULL) {
}

AudioCallbackCombined::AudioCallbackCombined(PPB_Audio_Callback callback)
    : callback_1_0_(NULL),
      callback_(callback) {
}

AudioCallbackCombined::~AudioCallbackCombined() {
}

bool AudioCallbackCombined::IsValid() const {
  return callback_1_0_ || callback_;
}

void AudioCallbackCombined::Run(void* sample_buffer,
                                uint32_t buffer_size_in_bytes,
                                PP_TimeDelta latency,
                                void* user_data) const {
  if (callback_) {
    callback_(sample_buffer, buffer_size_in_bytes, latency, user_data);
  } else if (callback_1_0_) {
    callback_1_0_(sample_buffer, buffer_size_in_bytes, user_data);
  } else {
    NOTREACHED();
  }
}

PPB_Audio_Shared::PPB_Audio_Shared()
    : playing_(false),
      shared_memory_size_(0),
#if defined(OS_NACL)
      thread_id_(0),
      thread_active_(false),
#endif
      user_data_(NULL),
      client_buffer_size_bytes_(0),
      bytes_per_second_(0),
      buffer_index_(0) {
}

PPB_Audio_Shared::~PPB_Audio_Shared() {
  // Shut down the socket to escape any hanging |Receive|s.
  if (socket_.get())
    socket_->Shutdown();
  StopThread();
}

void PPB_Audio_Shared::SetCallback(const AudioCallbackCombined& callback,
                                   void* user_data) {
  callback_ = callback;
  user_data_ = user_data;
}

void PPB_Audio_Shared::SetStartPlaybackState() {
  DCHECK(!playing_);
#if !defined(OS_NACL)
  DCHECK(!audio_thread_.get());
#else
  DCHECK(!thread_active_);
#endif
  // If the socket doesn't exist, that means that the plugin has started before
  // the browser has had a chance to create all the shared memory info and
  // notify us. This is a common case. In this case, we just set the playing_
  // flag and the playback will automatically start when that data is available
  // in SetStreamInfo.
  playing_ = true;
  StartThread();
}

void PPB_Audio_Shared::SetStopPlaybackState() {
  DCHECK(playing_);
  StopThread();
  playing_ = false;
}

void PPB_Audio_Shared::SetStreamInfo(
    PP_Instance instance,
    base::SharedMemoryHandle shared_memory_handle,
    size_t shared_memory_size,
    base::SyncSocket::Handle socket_handle,
    PP_AudioSampleRate sample_rate,
    int sample_frame_count) {
  socket_.reset(new base::CancelableSyncSocket(socket_handle));
  shared_memory_.reset(new base::SharedMemory(shared_memory_handle, false));
  shared_memory_size_ = shared_memory_size;
  bytes_per_second_ = kAudioOutputChannels * (kBitsPerAudioOutputSample / 8) *
                      sample_rate;
  buffer_index_ = 0;

  if (!shared_memory_->Map(shared_memory_size_)) {
    PpapiGlobals::Get()->LogWithSource(
        instance,
        PP_LOGLEVEL_WARNING,
        std::string(),
        "Failed to map shared memory for PPB_Audio_Shared.");
  } else {
    audio_bus_ = media::AudioBus::WrapMemory(
        kAudioOutputChannels, sample_frame_count, shared_memory_->memory());
    // Setup integer audio buffer for user audio data.
    client_buffer_size_bytes_ =
        audio_bus_->frames() * audio_bus_->channels() *
        kBitsPerAudioOutputSample / 8;
    client_buffer_.reset(new uint8_t[client_buffer_size_bytes_]);
  }

  StartThread();
}

void PPB_Audio_Shared::StartThread() {
  // Don't start the thread unless all our state is set up correctly.
  if (!playing_ || !callback_.IsValid() || !socket_.get() ||
      !shared_memory_->memory() || !audio_bus_.get() || !client_buffer_.get() ||
      bytes_per_second_ == 0)
    return;
  // Clear contents of shm buffer before starting audio thread. This will
  // prevent a burst of static if for some reason the audio thread doesn't
  // start up quickly enough.
  memset(shared_memory_->memory(), 0, shared_memory_size_);
  memset(client_buffer_.get(), 0, client_buffer_size_bytes_);
#if !defined(OS_NACL)
  DCHECK(!audio_thread_.get());
  audio_thread_.reset(new base::DelegateSimpleThread(
      this, "plugin_audio_thread"));
  audio_thread_->Start();
#else
  // Use NaCl's special API for IRT code that creates threads that call back
  // into user code.
  if (NULL == thread_functions.thread_create ||
      NULL == thread_functions.thread_join)
    return;

  int result = thread_functions.thread_create(&thread_id_, CallRun, this);
  DCHECK_EQ(result, 0);
  thread_active_ = true;
#endif
}

void PPB_Audio_Shared::StopThread() {
#if !defined(OS_NACL)
  if (audio_thread_.get()) {
    // In general, the audio thread should not do Pepper calls, but it might
    // anyway (for example, our Audio test does CallOnMainThread). If it did
    // a pepper call which acquires the lock (most of them do), and we try to
    // shut down the thread and Join it while holding the lock, we would
    // deadlock. So we give up the lock here so that the thread at least _can_
    // make Pepper calls without causing deadlock.
    CallWhileUnlocked(base::Bind(&base::DelegateSimpleThread::Join,
                                 base::Unretained(audio_thread_.get())));
    audio_thread_.reset();
  }
#else
  if (thread_active_) {
    // See comment above about why we unlock here.
    int result = CallWhileUnlocked(thread_functions.thread_join, thread_id_);
    DCHECK_EQ(0, result);
    thread_active_ = false;
  }
#endif
}

#if defined(OS_NACL)
// static
void PPB_Audio_Shared::SetThreadFunctions(
    const struct PP_ThreadFunctions* functions) {
  DCHECK(thread_functions.thread_create == NULL);
  DCHECK(thread_functions.thread_join == NULL);
  thread_functions = *functions;
}

// static
void PPB_Audio_Shared::CallRun(void* self) {
  PPB_Audio_Shared* audio = static_cast<PPB_Audio_Shared*>(self);
  audio->Run();
}
#endif

void PPB_Audio_Shared::Run() {
  int pending_data = 0;
  while (sizeof(pending_data) ==
         socket_->Receive(&pending_data, sizeof(pending_data))) {
    // |buffer_index_| must track the number of Receive() calls.  See the Send()
    // call below for why this is important.
    ++buffer_index_;
    if (pending_data < 0)
      break;

    PP_TimeDelta latency =
        static_cast<double>(pending_data) / bytes_per_second_;
    callback_.Run(client_buffer_.get(), client_buffer_size_bytes_, latency,
                  user_data_);

    // Deinterleave the audio data into the shared memory as floats.
    audio_bus_->FromInterleaved(
        client_buffer_.get(), audio_bus_->frames(),
        kBitsPerAudioOutputSample / 8);

    // Let the other end know which buffer we just filled.  The buffer index is
    // used to ensure the other end is getting the buffer it expects.  For more
    // details on how this works see AudioSyncReader::WaitUntilDataIsReady().
    size_t bytes_sent = socket_->Send(&buffer_index_, sizeof(buffer_index_));
    if (bytes_sent != sizeof(buffer_index_))
      break;
  }
}

}  // namespace ppapi